When jumping down the ledge, out of the two chests to the south, only the bottom one is real. Out of the two chests to the right, the left is real. Out of the next two chests, the top one is real. Out of the next two chests, the left one is real. Out of the three chests, the top and right are real. Out of the two chests to the right of those, only the right one is real.